Table 3. Theoretical and Experimental Zone-Center IR Modes for Ni3V2O8 and Co3V2O8a.
| DFT |
experimental |
|||||
|---|---|---|---|---|---|---|
| mode | ω0 (TO) | ω0 (LO) | ω0 (TO) | γ0 (TO) | ω0 (LO) | γ0 (LO) |
| Ni3V2O8 | ||||||
| B111u | 653 | 710 | 630(1) | 24(4) | 688(1) | 16(3) |
| B93u | 793 | 872 | 797(1) | 19(3) | 902(1) | 7(3) |
| B121u | 796 | 806 | 791(1) | 14(6) | 803(1) | 8(4) |
| B131u | 821 | 895 | 828(1) | 6(3) | 901(1) | 17(4) |
| Co3V2O8 | ||||||
| B111u | 636 | 691 | 626(1) | 11(3) | 684(1) | 16(3) |
| B93u | 806 | 860 | 789(1) | 10(3) | 895(1) | 6(4) |
| B121u | 770 | 779 | 759(1) | 25(5) | 787(1) | 17(5) |
| B131u | 820 | 874 | 819(1) | 8(4) | 885(1) | 12(5) |
a
γ0 is the damping factor of the fitting in cm–1, and ω0 is expressed in cm–1. The DFT-calculated ω0 has a related uncertainty of ±5%.